Aspects of the present disclosure relate generally to cables, such as fiber optic cables, that may support and carry optical fibers as well as other cable components.
Fiber optic cable, especially those in jurisdictions and applications with strict fire and smoke regulations, are designed to minimize the spread of fire, smoke, poisonous gases, and other hazards related to fire. Often thick jackets of flame-retardant (FR) and Low Smoke Zero Halogen (LSZH) materials are used to meet the demand for these types of fiber optic cables. However, these types of cables are often intended for installation into ducts that depends on an installation method whereby the cable is blown or jetted into the duct. Therefore, a cable jacket is needed that provides the benefits of FR and LSZH materials to pass international burn tests, such as IEC 60332-1-2 (single cable burn test), IEC 61034 (smoke density), and IEC 60332-3-24 (bunch cable burn test), and also have the strength and durability to withstand the stresses of installation, such as compression forces, impact and bending stresses, while providing a low coefficient of friction in order to provide the necessary blowing performance during installation.
LSZH materials utilize a high percentage of filler particles, such as magnesium hydroxide, aluminum hydroxide and other suitable materials, which result in a very low ultimate elongation of the material, especially at elevated temperatures. This low ultimate elongation of LSZH materials can lead to jacket cracking when cable products are subjected to typical handling and installation loads.